implements weeks_ago and prev_week for Date/DateTime/Time [#5122 state:committed]

1 files changed, 14 insertions, 2 deletions

diff --git a/activesupport/lib/active_support/core_ext/date/calculations.rb b/activesupport/lib/active_support/core_ext/date/calculations.rb
index 1856b4dd8b..f34185f22c 100644
--- a/activesupport/lib/active_support/core_ext/date/calculations.rb
+++ b/activesupport/lib/active_support/core_ext/date/calculations.rb
@@ -5,6 +5,8 @@ require 'active_support/core_ext/date/zones'
 require 'active_support/core_ext/time/zones'
 
 class Date
+  DAYS_INTO_WEEK = { :monday => 0, :tuesday => 1, :wednesday => 2, :thursday => 3, :friday => 4, :saturday => 5, :sunday => 6 }
+
   if RUBY_VERSION < '1.9'
     undef :>>
 
@@ -127,6 +129,11 @@ class Date
     )
   end
 
+  # Returns a new Date/DateTime representing the time a number of specified weeks ago.
+  def weeks_ago(weeks)
+    advance(:weeks => -weeks)
+  end
+
   # Returns a new Date/DateTime representing the time a number of specified months ago.
   def months_ago(months)
     advance(:months => -months)
@@ -185,10 +192,15 @@ class Date
   alias :sunday :end_of_week
   alias :at_end_of_week :end_of_week
 
+  # Returns a new Date/DateTime representing the start of the given day in the previous week (default is Monday).
+  def prev_week(day = :monday)
+    result = (self - 7).beginning_of_week + DAYS_INTO_WEEK[day]
+    self.acts_like?(:time) ? result.change(:hour => 0) : result
+  end
+
   # Returns a new Date/DateTime representing the start of the given day in next week (default is Monday).
   def next_week(day = :monday)
-    days_into_week = { :monday => 0, :tuesday => 1, :wednesday => 2, :thursday => 3, :friday => 4, :saturday => 5, :sunday => 6}
-    result = (self + 7).beginning_of_week + days_into_week[day]
+    result = (self + 7).beginning_of_week + DAYS_INTO_WEEK[day]
     self.acts_like?(:time) ? result.change(:hour => 0) : result
   end